It is known in prior art systems that energy transfer loops can be installed in the earth. These energy transfer loops generally consist of a length of tubing that is buried in the earth a desired distance so that a fluid passing through the tubing will experience heat transfer effects with the area of the earth in which the tubing extends. In certain circumstances, these energy transfer loops are operated in association with heating and air conditioning systems associated with commercial establishments and residential buildings. The energy transfer loop is used in association with or in place of such conventional energy transfer systems in which air is passed over refrigerant loops for the purposes of creating the air conditioning or heating effects.
For example, in warm weather environments, during times when air conditioning is required, air conditioning refrigerant fluid is caused to expand and subsequently yield the desired cooling effects. When the air conditioning refrigerant fluid is again compressed prior to the next expansion cooling cycle, this fluid becomes hot as a result of the compression. Current conventional air conditioning systems force ambient air over this refrigerant fluid to cool it before the next compression cycle. As the geothermal temperatures of the earth's soil are significantly cooler than the ambient air, use of the cooler fluid which has circulated through energy transfer loops installed in the earth, will provide greater heat transfer effects. As such, the overall efficiency of the air conditioning process improves and the energy requirements are significantly reduced
In heating systems, the temperature of the earth will be elevated relative to the ambient temperature. As a result, the energy transfer loop will pass through the earth so as to generally warm the cooled fluid within the loop. As a result, the energy requirements for elevating the temperature of the cool fluid within the loop are reduced which function opposite to the process described hereinabove.
Unfortunately, in the past, the cost of installing such energy transfer loops in the earth has been considerable. The economic cost for installing such loops can offset any beneficial energy saving costs and effects. As a result homeowners and business owners have avoided the use of such energy transfer loops in view of the considerable capital cost involved during the processes of installing the loop. Conventionally, a drilling contractor must be called so as to form the borehole in the earth. The driller will bring a great deal of drilling equipment to the desired location and begin the drilling activities. In certain circumstances, the earth will include rock formations which will require rather complex drilling activities. Still, in other circumstances, drilling equipment can be damaged because of the rock formations in the earth. In any circumstance, the cost of contracting with a driller to form the required borehole in the earth will greatly add to the capital cost of the air conditioning and/or heating system.
In certain areas of the country, such as the Gulf Coast, the surface of the earth is formed of an unconsolidated soil. This unconsolidated-type soil is easily displaced. As a result, the use of drills, and other boring equipment, can be an “overkill” in order to establish the requisite size of borehole for subsequent loop installation. Additionally, in such unconsolidated-type soils, the earth can often collapse in on itself during the drilling activity so as to make the formation of a borehole difficult and ineffective. This further complicates the goal of loop installation.
In the past, various patents have issued relating to the installation to the installation of such heat transfer loops. For example, U.S. Pat. No. 5,590,715, issued on Jan. 7, 1997 to T. R. Amerman, describes an underground heat exchange system. This system employs the installation of a pipe loop and a grout pipe in a wellbore. The system is used to grout the wellbore by releasing the grout pipe from the pipe loop or from a bottom member connected to the pipe loop, and then introducing grout through the pipe into the wellbore as the grout pipe is removed upwardly from the wellbore.
U.S. Pat. No. 5,758,724, issued on Jun. 2, 1998 to T. R. Amerman, also describes a method for simultaneously installing a pipe loop in the earth. In this patent, a coiled tubing unit is used to drill heat loop boreholes. The coiling tubing unit has a reel on which is wrapped a continuous flexible steel tubing, an injector which transports the tubing into and out of the hole, a drill bit on the end of a downhole motor, and a pump which supplies fluid for drilling. The motor is rotated by the pump pressure from the surface which allows the unit to drill. A grouting pipe is held in the bottom member. A pulling force applied to the grouting pipe releases it from the bottom member for removal from the wellbore as grout flows out from the bottom of the grouting pipe.
U.S. Pat. No. 6,041,862, issued on Mar. 28, 2000 to T. R. Amerman, teaches a ground heat exchange system which employs a heat loop, a reel of coil tubing releasably attached to the heat loop, and a curved member secured to the lower end of the heat loop. The coil tubing is used for pushing the heat loop into the borehole. The borehole is formed by directly drilling into the surface of the earth a desired distance. Subsequent to installation, the grouting pipe can be removed by applying a pulling force thereto.
U.S. Pat. No. 6,250,371, issued on Jun. 26, 2001 to Amerman et al., discloses an energy loop transfer system. This system employs a means for measuring the amount of energy transferred, a means for invoicing for the energy transferred, and the energy transfer system. The energy transfer system has a wellbore loop in the earth extending from the surface of the earth toward a bottom of the wellbore, a loop disposed in the wellbore and extending toward the bottom of the wellbore and a bottom member. The bottom member has a body with a first bore and second bore in which the second bore is not in fluid communication with the first bore.
The problem with these prior art systems described in the aforementioned Amerman patents is that a complex drilling activity is required. In particular, each of these systems requires that a drilling apparatus being employed for the purpose of drilling a borehole into the earth. In certain of these patents, the drilling apparatus actually includes a fluid-activated drill so that directional drilling can be achieved. Subsequent to forming the borehole into the earth, these prior art patents require that a grouting process be used so as to seal the borehole. This employs the passing of grout through the bottom member of the energy loop. The grouting material is passed through the piping so as to extend around the periphery of the energy loop. Analyses associated with these systems have indicated that they are not very cost effective when employed in soft soil conditions, such as those in the Gulf Coast region. Large costs associated with drilling and casing will offset the beneficial energy savings associated with such energy loop systems.
It is an object of the present invention to provide a method and an apparatus for forming and/or installing an energy transfer loop which is effective in soft soil conditions.
It is another object of the present invention to provide a method and an apparatus for forming and/or installing an energy transfer loop which minimizes the cost associated with the excavation of the earth.
It an other object of the present invention to provide a method and an apparatus for forming and/or installing an energy transfer loop in which the liquid delivery piping can be removed subsequent to installation.
It is a further object of the present invention to provide a method and an apparatus for forming and/or installing an energy transfer loop which maximizes the energy transfer effects between the earth and the fluid passing through the energy transfer loop.
It is still another object of the present invention to provide a method and an apparatus for forming and/or installing an energy transfer loop which is cost effective, easy to use and time efficient.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.